Calibration Square Variance

[CCRN]

I downloaded and printed the 20 x 20 x 2 square using S3D and it is measuring 19.85 x 19.82 x 2.34. What should the S3D profile settings be for this print? Maybe my profile wasn't proper.

Thanks,

Jerold

[CCRN]

Tried the square a second time with the default M2 profile at default settings. Still getting 19.85 x 19.86 x 2.31. How do I get these numbers to more closely match the design specs?

Thanks,
Jerold

[CCRN]

Just found this thread and working through it.

viewtopic.php?f=3&t=1964&hilit=calibration+cube

[Jules]

The 2.34 mm measurement is a bit high, indicating that the Starting Height is just a little bit off. Make the gap just a hair's width smaller and it will take care of that.

Practically speaking, the other measurements are fine, they are within 0.2mm overall across 20 mm. (And most calipers cannot measure that accurately.) It's not going to be worth the amount of effort required to try to fine tune them further.

If your prints are sticking well though, you really don't need to worry about the slight variance on the height either. My Rev.E machine causes that 2.0 mm tall square to measure 2.12 -2.13 mm.
(I suspect it has to do with firmware changes in the Rev.E models. The mechanical gap that we set is exactly 0.13 mm.)

[Jules]

Just found this thread and working through it.

viewtopic.php?f=3&t=1964&hilit=calibration+cube

If you have a Rev.E machine, you do not need to do that.

[CCRN]

Will recalibrate starting height once my print finishes. It is a Rev E. Machine. What gets me is settings where there is "slight resistance" with the feeler gauge. If you bend the endit feels resistance but then lay the feeler flat and it disappears. That may be my issue.

[Jules]

Yeah, it helps to get down at eye level with the tip of the nozzle when you set it. (Other than that, it looks fine. Don't waste a lot of time. Rev.E users have all of that taken care of for them.)

[CCRN]

So with Rev E. there is no need to calibrate the extrusion multiplier in S3D?

[Jules]

Well, you can, just for grins, if you've got nothing else to do. You'll probably be "close enough for government work" though, extrusion width-wise, so it doesn't usually gain you much. Every time I tried to calibrate the RevE results, they were right on the money.

(Remember, most of the guys & gals on the forum who answer questions here are using the older style machines. Those needed to be calibrated for extrusion width. Your machine generally doesn't.)

If you have a problem with something fitting too tightly, check the design. They need to have some leeway built into the spaces between tabs and slots from the get-go. It's part of the design process for this kind of manufacturing.

And unfortunately, squirting hot plastic is not an exact science. Too many variables. 0.2 mm tolerance is average, and generally results in a "snug" fit. 0.1 mm is really tight. 0.3 mm is a loose fit.

And there are many, many bad designs on Thingiverse, because these tolerances were not included. Do some experimenting with your own designs to see which works best for you.

[CCRN]

Printed a new square after setting the z height and have 19.95 x 19.94 x 2.05. I think I should be happy with that and get back to printing!

Could not get the outline of the cube to print as described here.

This is the design from https://softsolder.com/2014/04/18/revis ... on-object/ looks like this in S3D

Design

then slices to this

Sliced

Screen Shot 2016-08-10 at 1.46.43 PM.png (24.7 KiB) Viewed 12134 times

I am at 0.20 height and 0.40 for width, which matches the dimensions in OpenSCAD. Curious what I might be doing wrong here.